Recently, a secondary battery, which can be charged and discharged, has been widely used as an energy source for wireless mobile devices. Also, the secondary battery has attracted considerable attention as a power source for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (Plug-In HEV), which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuels.
Small-sized mobile devices use one or several battery cells for each device. On the other hand, middle or large-sized devices, such as vehicles, uses a middle or large-sized battery module having a plurality of battery cells electrically connected to one another because high power and large capacity are necessary for the middle or large-sized devices.
Preferably, the battery module is manufactured so as to have as small a size and weight as possible. For this reason, a prismatic battery or a pouch-shaped battery, which can be stacked with high integration and has a small weight to capacity ratio, is usually used as a battery cell of the middle or large-sized battery module. In particular, much interest is currently focused on the pouch-shaped battery, which uses an aluminum laminate sheet as a sheathing member, because the pouch-shaped battery is lightweight, and the manufacturing costs of the pouch-shaped battery are low.
Also, the battery module is constituted by combining a plurality of battery cells, and therefore, safety and operational efficiency of the battery module assembly is greatly lowered when some of the battery cells suffer from overvoltage, overcurrent, or overheating. For this reason, means to sense and control overvoltage, overcurrent, or overheating are needed. Consequently, voltage sensors are connected to the battery cells to check and control operational states of the battery cells in real time or at predetermined intervals. Installation or connection of such sensing means very complicate a process of assembling the battery module. Furthermore, a plurality of wires is needed to install or connect the sensing means with the result that a short circuit may occur in the battery module. Also, the secondary battery is used as a power source for vehicles as a result of extension of the application range of the secondary battery. When strong impact or vibration is applied to the battery module, therefore, fastening means to stably maintain contact of the sensing means are needed.
In addition, in a case in which the battery module is constructed using a plurality of battery cells or a plurality of cell modules, each of which includes a predetermined number of battery cells, a plurality of members for mechanical fastening and electrical connection therebetween is generally needed with the result that a process of assembling the mechanical fastening and electrical connection members is very complicated.
Furthermore, there is needed a space for coupling, welding, or soldering of the mechanical fastening and electrical connection members with the result that the total size of the battery system is increased. The increase in size of the battery system is not preferred in the above regard. Consequently, there is a high necessity for a voltage sensing assembly which is compact and has excellent structural stability and a battery module including the same.